I started the test after building this test environment:
Three Energizer max AA cells power the IoT Node. Normally the IoT Node sleeps.
After pressing the reset button the IoT Node is connecting to the home network via Wifi, measured the battery voltage, and send a message to IFTTT.
There are two IFTTT receipts. One sends a Twitter direct message (to me) and the other makes an entry into a Google spreadsheet. Follow the link to see decharging my power pack by this IoT button app.